This study introduces a novel vertical bending continuous casting technology for producing thin slabs of pure aluminum and aluminum alloys, offering significant advancements over traditional vertical casting methods. The newly designed equipment and optimized process parameters enable the continuous casting of pure aluminum 1070 at a speed of 1.2 m/min, surpassing the casting speed of conventional direct-chill casting. Comprehensive investigations of the macrostructure and microstructure of the cast pure aluminum 1070 reveal a refined equiaxed crystal structure with an average grain size of 98 μm, significantly smaller than that obtained through conventional casting processes. This refinement in grain size is expected to enhance the material’s mechanical properties and processing capabilities. Additionally, simulations of the temperature distribution and solidification structure provide insights into the formation of a “U”-shaped sump and liquidus isotherms, which are crucial for understanding the solidification dynamics of the material. The refined grain structure and increased casting speed demonstrate substantial potential for advancing aluminum alloy production, especially in applications requiring superior performance and more efficient manufacturing processes.
Carlos Antón-Plágaro, Kai-en Chen, Qian Guo
et al.
Abstract Endosomal retrieval and recycling of integral cargo proteins is essential for cell and organism development and homeostasis and is orchestrated through a specialised endosomal nanodomain, the retrieval sub-domain. Sub-domain dysfunction is associated with human disease, but our mechanistic understanding of its function remains poorly described. Here, using proximity proteomics of retrieval sub-domain components Retromer and Retriever we identify mechanistic details of retrieval sub-domain composition and organization, including an unrecognised complexity in the interface with RAB GTPase switching. Combining X-ray crystallography and in silico predictions with biochemical and cellular analysis, we reveal that Retromer directly associates and recruits the RAB10 regulators DENND4A, DENND4C, TBC1D1, and TBC1D4, and the RAB35 regulator TBC1D13 to regulate retrieval sub-domain function. The retrieval sub-domain therefore constitutes a hub for integrating cargo recycling with the regulated switching of selected RAB GTPases. We propose this constitutes a major component of the neuroprotective role of the retrieval sub-domain.
Radostina Palcheva, Luděk Kaluža, Tanya Petrova
et al.
Tri-metallic NiMoW catalysts prepared by impregnating mesoporous aluminas (pore sizes of ~9 nm and surface areas of ~225 m<sup>2</sup>/g) obtained by sol-gel (NiMoW/Al) and hydrothermal (NiMoW/Al<sub>HYDT</sub>) processes were investigated in the hydrodesulfurization (HDS) of thiophene and 4,6-dimethyldibenzothiophene (4,6-DMDBT) at H<sub>2</sub> pressures of 1 MPa and 5.0 MPa, respectively. The supports and catalysts were characterized by N<sub>2</sub> physisorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), temperature-programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HRTEM). The NiMoW/Al<sub>HYDT</sub> catalyst, which was the most active in both test HDS reactions, was characterized by a pore size of 7.5 nm, whereas the pore size of the catalyst on sol-gel alumina (NiMoW/Al) was only 4.8 nm. Moreover, the NiMoW/Al<sub>HYDT</sub> catalyst exhibited reduction peaks shifted to a lower temperature during TPR, indicating weaker metal support interactions, a higher degree of Mo (79%) and W (48%) sulfidation, and an optimal layer slab length distribution of Mo(W)S<sub>2</sub> nanocrystals preferentially between 2–4 nm with an average layer stacking of 1.7 compared to the NiMoW/Al counterpart.
Supeshala Nawarathnage, Sara Soleimani, Moriah H. Mathis
et al.
While conducting pilot studies into the usefulness of fusion to TELSAM polymers as a potential protein crystallization strategy, we observed novel properties in crystals of two TELSAM–target protein fusions, as follows. (i) A TELSAM–target protein fusion can crystallize more rapidly and with greater propensity than the same target protein alone. (ii) TELSAM–target protein fusions can be crystallized at low protein concentrations. This unprecedented observation suggests a route to crystallize proteins that can only be produced in microgram amounts. (iii) The TELSAM polymers themselves need not directly contact one another in the crystal lattice in order to form well-diffracting crystals. This novel observation is important because it suggests that TELSAM may be able to crystallize target proteins too large to allow direct inter-polymer contacts. (iv) Flexible TELSAM–target protein linkers can allow target proteins to find productive binding modes against the TELSAM polymer. (v) TELSAM polymers can adjust their helical rise to allow fused target proteins to make productive crystal contacts. (vi). Fusion to TELSAM polymers can stabilize weak inter-target protein crystal contacts. We report features of these TELSAM–target protein crystal structures and outline future work needed to validate TELSAM as a crystallization chaperone and determine best practices for its use.
In order to study the basic principles of vibration-excited liquid metal nucleation technology, a coupled model to connect the temperature field calculated by ANSYS Fluent and the dendritic growth simulated by cellular automaton (CA) algorithm was proposed. A two-dimensional CA model for dendrite growth controlled by solute diffusion and local curvature effects with random zigzag capture rule was developed. The proposed model was applied to simulate the temporal evolution of solidification microstructures under different degrees of surface undercooling and vibration frequency of the crystal nucleus generator conditions. The simulation results showed that the predicted columnar dendrites regions were more developed, the ratio of interior equiaxed dendrite reduced and the size of dendrites increased with the increase of the surface undercooling degrees on the crystal nucleus generator. It was caused by a large temperature gradient formed in the melt. The columnar-to-equiaxed transition (CET) was promoted, and the refined grains and homogenized microstructure were also achieved at the high vibration frequency of the crystal nucleus generator. The influences of the different process parameters on the temperature gradient and cooling rates in the mushy zone were investigated in detail. A lower cooling intensity and a uniform temperature gradient distribution could promote nucleation and refine grains. The present research has guiding significance for the process parameter selection in the actual experimental.
Raphaël de Wijn, Oliver Hennig, Jennifer Roche
et al.
Determining optimal conditions for the production of well diffracting crystals is a key step in every biocrystallography project. Here, a microfluidic device is described that enables the production of crystals by counter-diffusion and their direct on-chip analysis by serial crystallography at room temperature. Nine `non-model' and diverse biomacromolecules, including seven soluble proteins, a membrane protein and an RNA duplex, were crystallized and treated on-chip with a variety of standard techniques including micro-seeding, crystal soaking with ligands and crystal detection by fluorescence. Furthermore, the crystal structures of four proteins and an RNA were determined based on serial data collected on four synchrotron beamlines, demonstrating the general applicability of this multipurpose chip concept.
Waveguides formed by etching, proton-exchange (PE), and strip-loaded on single-crystal lithium niobate (LN) thin film were designed and simulated by a full-vectorial finite difference method. The single-mode condition, optical power distribution, and bending loss of these kinds of waveguides were studied and compared systematically. For the PE waveguide, the optical power distributed in LN layer had negligible change with the increase of PE thickness. For the strip-loaded waveguide, the relationships between optical power distribution in LN layer and waveguide thickness were different for quasi-TE (q-TE) and quasi-TM (q-TM) modes. The bending loss would decrease with the increase of bending radius. There was a bending loss caused by the electromagnetic field leakage when the neff of q-TM waveguide was smaller than that of nearby TE planar waveguide. LN ridge waveguides possessed a low bending loss even at a relatively small bending radius. This study is helpful for the understanding of waveguide structures as well as for the optimization and the fabrication of high-density integrated optical components.
In the title molecular complex, [Ni(C3H5OS2)2(C5H4BrN)2], the Ni2+ cation is located on a centre of inversion and has a distorted octahedral N2S4 environment defined by two chelating xanthate ligands and two monodentate pyridine ligands. The C—S bond lengths of the thiocarboxylate group are indicative of a delocalized bond and the O—Csp2 bond is considerably shorter than the O—Csp3 bond, consistent with a significant contribution of one resonance form of the xanthate anion that features a formal C=O+ unit and a negative charge on each of the S atoms. The packing of the molecules is stabilized by C—H...S and C—H...π interactions. In addition, π–π interactions between the pyridine rings [centroid-to-centroid distance = 3.797 (3) Å] are also present. In the crystal structure, molecules are arranged in rows along [100], forming layers parallel to (010) and (001).
S. Rizwana Begum, R. Hema, R. Venkateswaramoorthi
et al.
The asymmetric unit of the title compound, C22H23F2NO, contains two independent molecules, A and B. The bicyclic system adopts a twin-chair conformation in both molecules. The dihedral angles between the fluorophenyl rings are 55.27 (8) and 56.37 (7)° in molecules A and B, respectively. The NH groups are not involved in hydrogen bonding due to the steric hindrance of fluorophenyl groups. The crystal structure features weak C—H...O interactions.
Modou Sarr, Waly Diallo, Aminata Diasse-Sarr
et al.
The crystal structure of the title compound, (C6H14N)3[Sn(C2O4)2Cl2]Cl·H2O, contains three cyclohexylammonium cations, one stannate(IV) dianion, one isolated chloride anion and one lattice water molecule. The cyclohexylammonium cations adopt chair conformations. In the complex anion, two bidentate oxalate ligands and two chloride anions in cis positions coordinate octahedrally to the central SnIV atom. The cohesion of the molecular entities is ensured by the formation of N—H...O, O—H...O, O—H...Cl and N—H...Cl interactions involving cations, anions and the lattice water molecule, giving rise to a layer-like arrangement parallel to (010).
In the title compound, C17H15N3OS, the phenothiazine ring system is slightly bent, with a dihedral angle of 13.68&#8197;(7)&#176; between the benzene rings. The dihedral angle between the oxadiazole ring and the adjacent benzene ring is 7.72&#8197;(7)&#176;. In the crystal, a &#960;&#8211;&#960; interaction with a centroid&#8211;centroid distance of 3.752&#8197;(2)&#8197;&#197; is observed between the benzene rings of neighbouring molecules.
Adenovirus (AdV) capsid organization is considerably complex, not only because of its large size (~950 Å) and triangulation number (<em>pseudo </em>T = 25), but also because it contains four types of minor proteins in specialized locations modulating the quasi-equivalent icosahedral interactions. Up until 2009, only its major components (hexon, penton, and fiber) had separately been described in atomic detail. Their relationships within the virion, and the location of minor coat proteins, were inferred from combining the known crystal structures with increasingly more detailed cryo-electron microscopy (cryoEM) maps. There was no structural information on assembly intermediates. Later on that year, two reports described the structural differences between the mature and immature adenoviral particle, starting to shed light on the different stages of viral assembly, and giving further insights into the roles of core and minor coat proteins during morphogenesis [1,2]. Finally, in 2010, two papers describing the atomic resolution structure of the complete virion appeared [3,4]. These reports represent a veritable <em>tour de force</em> for two structural biology techniques: X-ray crystallography and cryoEM, as this is the largest macromolecular complex solved at high resolution by either of them. In particular, the cryoEM analysis provided an unprecedented clear picture of the complex protein networks shaping the icosahedral shell. Here I review these latest developments in the field of AdV structural studies.
The title compound, [Mn(C11H8O5)(C12H8N2)(H2O)2]&#183;H2O, was obtained under hydrothermal conditions. The coordination environment of the Mn(II) atom is a distorted MnN2O4 octahedron defined by two N atoms from 1,10-phenanthroline, two water O atoms and two carboxylate O atoms from two acrylate anions. The bis-monodentate coordination mode of the anion leads to the formation of chains propagating in [010]. Intermolecular O&#8212;H...O hydrogen bonds link the chains into a two-dimensional network parallel to (100). In the voids of this arrangement, disordered lattice water molecules are present.
Islam Ullah Khan, Ifrah Naseer, Irfana Mariam
et al.
In the title compound, C14H15NO3S, the dihedral angle between the aromatic rings is 59.39&#8197;(14)&#176; and the C&#8212;S&#8212;N&#8212;C torsion angle is &#8722;71.4&#8197;(2)&#176;. In the crystal, a supramolecular chain running along the b axis with a C(4) graph set is formed via N&#8212;H...O hydrogen bonds.
Tara Shahani, Hoong-Kun Fun, R. Venkat Ragavan
et al.
In the title compound, C11H17N3O3, the pyrazole ring is approximately planar, with a maximum deviation of 0.005&#8197;(2)&#8197;&#197;, and forms a dihedral angle of 5.69&#8197;(13)&#176; with the plane through the six atoms of the piperidine ring. In the crystal, pairs of intermolecular N&#8212;H...O hydrogen bonds form dimers with neighbouring molecules, generating R22(8) ring motifs. These dimers are further linked into two-dimensional arrays parallel to the bc plane by intermolecular N&#8212;H...O and C&#8212;H...O hydrogen bonds.
The title compound, [Sn2Cl6(OH)2(H2O)2]·2C4H10O, consists of a centrosymmetric molecule and two additional solvent molecules and has an infinite two-dimensional network extending parallel to (101). The Sn atom is six-coordinate with a distorted octahedral geometry. Additional O—H...O hydrogen bonding leads to stabilization of the crystal structure.